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SQLAlchemy: cascade delete
...use that is where you defined your relationship (it doesn't care that you called it "Child" of course).
If you define the relationship on the Parent class instead, it will work:
children = relationship("Child", cascade="all,delete", backref="parent")
(note "Child" as a string: this is allowed wh...
In a Django form, how do I make a field readonly (or disabled) so that it cannot be edited?
...hanged his example to work with Django 1.3, using get_readonly_fields.
Usually you should declare something like this in app/admin.py:
class ItemAdmin(admin.ModelAdmin):
...
readonly_fields = ('url',)
I've adapted in this way:
# In the admin.py file
class ItemAdmin(admin.ModelAdmin):
...
Is it possible to forward-declare a function in Python?
...rwards is impossible, what about defining it in some other module?
Technically you still define it first, but it's clean.
You could create a recursion like the following:
def foo():
bar()
def bar():
foo()
Python's functions are anonymous just like values are anonymous, yet they can be ...
How to calculate the difference between two dates using PHP?
...ferred way of doing this is like described by jurka below. My code is generally only recommended if you don't have PHP 5.3 or better.
Several people in the comments have pointed out that the code above is only an approximation. I still believe that for most purposes that's fine, since the usage of...
Running a specific test case in Django when your app has a tests directory
...
Checkout django-nose. It allows you to specify tests to run like:
python manage.py test another.test:TestCase.test_method
or as noted in comments, use the syntax:
python manage.py test another.test.TestCase.test_method
...
How to join strings in Elixir?
...your list size is arbitrary:
Enum.join(["StringA", "StringB"], " ")
... all of the solutions above will return
"StringA StringB"
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Getting number of elements in an iterator in Python
...ve an answer, this answer avoids instantiation of a list, and it is empirically faster by a constant than the reduce method listed above.
– Phillip Nordwall
Aug 2 '12 at 15:27
5
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How to manage client-side JavaScript dependencies? [closed]
...anage dependencies on the server side, I could not find any that satisfies all my needs to have a coherent client side JavaScript dependency management workflow. I want to satisfy these 5 requirements:
...
How do I parse an ISO 8601-formatted date?
... Pypi name is python-dateutil, not dateutil (thanks code3monk3y):
pip install python-dateutil
If you're using Python 3.7, have a look at this answer about datetime.datetime.fromisoformat.
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python: how to identify if a variable is an array or a scalar
I have a function that takes the argument NBins . I want to make a call to this function with a scalar 50 or an array [0, 10, 20, 30] . How can I identify within the function, what the length of NBins is? or said differently, if it is a scalar or a vector?
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